Re: [PATCH 15/18] x86 vDSO: consolidate vdso32

[Zachary Amsden <zach@vmware.com>]

On Mon, 2007-11-19 at 14:06 -0800, Roland McGrath wrote:
> This makes x86_64's ia32 emulation support share the sources used in the
> 32-bit kernel for the 32-bit vDSO and much of its setup code.
> 
> The 32-bit vDSO mapping now behaves the same on x86_64 as on native 32-bit.
> The abi.syscall32 sysctl on x86_64 now takes the same values that
> vm.vdso_enabled takes on the 32-bit kernel.  That is, 1 means a randomized
> vDSO location, 2 means the fixed old address.  The CONFIG_COMPAT_VDSO
> option is now available to make this the default setting, the same meaning
> it has for the 32-bit kernel.  (This does not affect the 64-bit vDSO.)

I think you should drop CONFIG_COMPAT_VDSO support for 32-bit VDSO on
64-bit kernel.  This was only to hack around a broken version of glibc
that shipped with SUSE PRO 9.0, which had broken assertions based on
misinterpretation of ELF fields.  64-bit machines will never see this
glibc and the hack can die.

Perhaps it is finally time to remove the hack from 32-bit as well, and
eliminate COMPAT_VDSO entirely?  Or does it really have to live forever.

Zach